1. Field of the Invention
The present invention relates to an image forming apparatus such a copying machine and a printer that adopts an electrophotographic system, and more particularly to operability when exchanging consumable supplies in the image forming apparatus including a plurality of image bearing members.
2. Description of Related Art
Utilized over the recent years as a multi-color or full-color image forming apparatus of the electrophotographic system is an in-line type image forming apparatus, wherein a plurality of photosensitive drums are arranged in one line corresponding to respective colors, and color toner images formed on the respective photosensitive drums are sequentially superposed on an intermediate transferring belt, thus forming color images. FIG. 5 shows a conventional in-line type image forming apparatus including the intermediate transferring member in the electrophotographic system.
Photosensitive drums 20Y, 20M, 20C, 20Bk, which are constructed by applying photosensitive layers over conductive bodies, are formed with electrostatic latent images by laser beams emitted from a scanning type optical device and constantly rotate at a predetermined speed. The numeral 21 represents the scanning type optical device for irradiating the laser beams on the basis of image information transmitted from an unillustrated image reader or a personal computer etc. This scanning type optical device employs a system in which one single polygon motor unit irradiates four pieces of photosensitive drums with the laser beams, and opposite surfaces of a polygon mirror are each formed with two scanning groups for irradiating plural lines of laser beams. Further, a plurality of return mirrors are used for attaining a compact configuration of the unit. The symbols 22Y, 22M, 22C, 22Bk designate developing devices for forming toner images on the photosensitive drums by toners that are tribo-charged on the photosensitive drums, the numeral 23 denotes an intermediate transferring belt which carries the toner images on the photosensitive drums onto a sheet for transferring, the numeral 24 represents a sheet feed cassette storing the sheets on which the toner images are formed, the numeral 25 represents a fixing device to have the transferred toner image absorbed on the sheet thermally, and the numeral 26 designates sheet discharge tray on which the image-fixed transfer sheets are stacked. The image formation is done such that the photosensitive drums are irradiated with the laser beams from the scanning type optical device 21 on the basis of the image information, and electrostatic latent images are formed on the charged photosensitive drums 20 by cleaners 27Y, 27M, 27C, 27Bk. Thereafter, the tribo-charged toners in the developing device are adhered onto the electrostatic latent images, thereby forming the toner images on the photosensitive drums. The toner images are transferred onto the intermediate transferring belt from on the photosensitive drums and again transferred onto the sheet conveyed from the sheet feed cassette 24 provided at a lower portion of the body, thereby forming the images on the sheet. The images transferred onto the sheet are fixed with the toners by the fixing device 25, and the image-formed sheet is stacked on the sheet discharge tray. FIG. 6 shows a schematic view for explaining an opening portion of the image forming apparatus. This image forming apparatus is provided with a front door 28 that opens and closes a recording material conveyance path and with a side door 29 through which consumable supplies are exchanged. The image forming apparatus is further provided with an opening portion 31 through which the intermediate transferring belt 30 is detachably attached and with opening portions 32, 33 through which the process cartridges and toner cartridges are detachably attached. Moreover, as follows, it is disclosed, the image forming apparatus in which exposing and developing are conducted by one image bearing member.
In the image forming apparatus, each of units provided to the rotational developing device is detachably attachable from an open/close portion provided in an upper surface of the apparatus.
The respective consumable supplies and the intermediate transferring belt have hitherto been, as shown in the conventional example, attached and detached via the side door, and therefore, on the occasion of installing the image forming apparatus body, it is required that a space for opening and closing the side door be ensured in a side surface portion. Further, in the case of placing the image forming apparatus on a desktop, it follows that a user stands on the front side (on the side of an opening/closing direction of a front door 28 with a fixing portion), and is required to perform an operation by stretching the hand toward the side surface portion in order to attach and detach the process cartridges to be exchanged from the image forming apparatus. Moreover, in the in-line type image forming apparatus described above, the process cartridge on the backside is disposed at a relatively far distance from the front surface portion, so that there declines operability for performing the attaching/detaching operation by stretching the hand from the lateral direction, and a space utilized for the user to go around sideways for conducting the operation is needed for avoiding this. Hence, there arises a problem of causing the decline of the operability in such a configuration.
It is therefore desirable to have a configuration enabling the process cartridges to be attached and detached in a state where the user stands on the front side of the image forming apparatus. In this respect, Japanese Patent Application Laid-Open Publication No. 2004-85899 discloses an image forming apparatus as shown in FIG. 7. In this art as the image forming apparatus, a lower surface exposure system in which the process cartridges are positioned under an intermediate transferring member and optical units are positioned further downwardly of the process cartridges. The process cartridges are taken out in the following procedure. Namely, the procedure is that the intermediate transferring member and a stack portion stacked with the outputted recording materials are integrally released in a perpendicular direction, and thereafter the process cartridges are taken out.
Depending on the attaching/detaching direction of the process cartridge as in Japanese Patent Application Laid-Open Publication No. 2003-208073 and Japanese Patent Application Laid-Open Publication No. 10-115961, however, the process cartridge interferes with the intermediate transferring member in an open/close cover. Consequently, problems occur, wherein the attaching/detaching operability declines, and the intermediate transferring member might be damaged.